Hall probes are known in the state-of-the-art. Generally, Hall probes comprise of a conducting sensor surface through which a feed current flows. If a magnetic field is now alternating with the sensor surface through which the current flows, a deviation of the charge carriers takes place, caused by the Lorentz force on the moving electrical charge carriers in the sensor surface, transversal to their direction of movement. Hereby, and the electric field, as well as a measurable electric voltage is created between the two edges on the sides of the sensor surface.
This voltage, known as the Hall voltage, is in proportion to the product of the magnetic flow density of the magnetic field which interacts with the sensor and the feed current which flows through the surface of the sensor. Hereby, by means of measuring the Hall voltage—and having a known feed current—the magnetic flow density interacting with the sensor can be up to a proportional factor, whereby the proportional factor is mainly dependent on the geometric dimensions of the sensor surface.
Such Hall probes or Hall sensors are known, for instance, as integrated Hall sensor components, whereby a processing device follows the actual Hall sensor, which processes the Hall signal provided by the Hall sensor for analysis and generates an output signal, resulting from the Hall signal. The Hall sensor, as well as the processing device, can hereby be integrated in one single enclosure.
Hall sensors can be used, for instance, to calculate the relative position of two mechanical components under a contact-free and wear-free position. Hereby, a Hall sensor is positioned at one of the two mechanical components, while a component which generates a magnetic field, preferably a permanent magnet, is positioned at the other, second mechanical part. During relative movement of the two mechanical components, the strength and/or the angle of the magnetic field lines of the part generates a magnetic field at the location of the Hall sensor, and thus the Hall voltage which is generated by the Hall sensor. Therefore, the change of the relative position of the two mechanical parts can be registered and, in the case of respective calibration of the Hall sensor, can also be measured or quantitatively calculated, respectively.
Basically, there is also a risk with the Hall sensor of a failure of the sensor component, for instance due to an electronic defect. It is also possible that the measured signal is distorted, for instance due to different operating temperatures, interfering, external magnetic fields, and mechanical stress which is transferred to the Hall sensor such that its sensitivity or characteristics, respectively, can change.
If a standard Hall sensor component fails due to such a defect, or distortions of the signal from the Hall sensor are created due to be described conditions, the problem often exists that the functionality of the Hall sensor component cannot be tested in the assembled state, or during the operation, respectively, so that a defect cannot be recognized. Even less options are offered by the state of the art in regard to the diagnosis of the Hall sensor component by itself, but also in regard to the evaluation electronics which are assigned to the Hall sensor and which are often, together with the actual sensor element, positioned in a standardized chip enclosure.
Known from the publication DE 100 47 994 A1 is a Hall sensor component in which diagnosis of the Hall sensor is possible in the assembled state where the current, which flows through the Hall sensor component, is changed in cycles and where the functionality of the sensor is assumed because of the change of the output voltage of the sensor. This teaching, however, only enables recognizing, by way of a quantitative analysis, whether the Hall sensor component and/or the following evaluation electronics function at all, or if a failure of one of the components has occurred. However, it is neither possible to recognize, during a failure, whether the actual Hall sensor component or the evaluation electronic is affected, nor can a quantitative analysis take place in such a way to check whether the output signal of the sensor has been distorted, for example, through external factors. It is also not possible in that teaching to recognize whether, for instance, the Hall sensor component is under mechanical stress, or whether the Hall sensor component has a different malfunction, or if it is indeed a change of the measured magnetic field.